Erigeron

Erigeron annuus - flower view 01

Erigeron bonariensis flowers

Erigeron is a large genus of plants in the Asteraceae family, which is also known as the daisy, aster, or sunflower family. The name "Erigeron" is derived from the Greek words "eri" meaning early, and "geron" meaning old man, a reference to the appearance of the white, hair-like tufts on the seeds of many Erigeron species, which resemble an old man's beard. This genus includes over 390 species, commonly referred to as fleabanes. Erigeron species are found in a wide range of habitats across the world, from tropical to temperate regions, and are especially abundant in North America.

Description

Erigeron plants can be annuals, perennials, or biennials. They are characterized by their daisy-like flowers, which usually have a large number of white, pink, purple, or sometimes yellow ray florets surrounding a central disc of yellow disc florets. The leaves of Erigeron species can be basal and/or cauline (stem leaves), with shapes ranging from linear to ovate. The plants vary greatly in size, from small, compact species only a few centimeters tall to larger species that can reach up to two meters in height.

Habitat and Distribution

Erigeron species are adaptable and can be found in a variety of habitats, including meadows, grasslands, forest clearings, and alpine zones. They are predominantly found in North America, with a significant number of species occurring in the western United States and Canada. However, the genus has a global distribution, with species also found in Europe, Asia, and South America.

Cultivation and Uses

Many Erigeron species are cultivated for their attractive flowers and are used in gardens and landscaping. They are known for their ability to thrive in poor soils and tolerate drought conditions, making them suitable for rock gardens and wildflower meadows. Some species, such as Erigeron karvinskianus, commonly known as Mexican fleabane, have become popular in horticulture. In addition to their ornamental value, some species of Erigeron have been used in traditional medicine for their purported anti-inflammatory and diuretic properties.

Conservation

While many Erigeron species are common and not considered at risk, there are several species that are rare and face threats from habitat loss, invasive species, and climate change. Conservation efforts are underway in various regions to protect these at-risk species and their habitats.

Taxonomy

The taxonomy of Erigeron is complex and has been the subject of much revision. The genus is closely related to other genera in the Asteraceae family, such as Aster and Bellis, and distinguishing between these genera can be challenging due to the similarities in their flower structures. Molecular phylogenetic studies have helped clarify the relationships within the genus and with related genera.

Selected Species

• Erigeron annuus (Eastern daisy fleabane)
• Erigeron karvinskianus (Mexican fleabane)
• Erigeron glaucus (Seaside daisy)
• Erigeron speciosus (Showy fleabane)

See Also

• Asteraceae
• Flora of North America
• Horticulture
• Conservation biology